Visualizing Tendon Elasticity in an ex Vivo Partial Tear Model

In Vivo Measures of Shear Wave Speed as a Predictor of Tendon Elasticity and Strength

“…First is the recognition that tendon exhibits strain-stiffening behavior at low loads (Fung 1993), such that one observes an increase in shear wave speed with tendon stretch. A monotonic increase in SWS with stretch has previously been observed in both in vivo (Aubry et al 2013; DeWall et al 2014b; Yeh et al 2014) and ex vivo (DeWall et al 2014a) studies. This stretch dependence can affect repeatability of SWS measures if posture and muscle loading are not well controlled.…”

“…4). SWS values within the range of 14-16.3 m/s (or corresponding modulus values) have previously been reported for tendon using the Aixplorer system (e.g., Aubry et al 2013; Aubry et al 2015; DeWall et al 2014a; DeWall et al 2014b; Yeh et al 2014), such that the effects of partial SWS saturation on study findings should be considered. In the present study, we repeated our correlation analysis using only those images that did not exhibit any SWS saturation and obtained similar results (r = 0.52, p < 0.001 for elastic modulus, and r = 0.60, p < 0.001 for ultimate stress) to those reported with the full data set (Table 1).…”

“…This study was undertaken to assess the potential of using the shear wave speed metric as a biomarker of tendon elasticity and ultimate strength following repair and healing. The results are encouraging, with a significant decrease in SWS observed after severing and surgically repairing a tendon, which may reflect a decrease in mechanical integrity of the damaged tissue (DeWall et al 2014a; Yeh et al 2013). Additionally, with all data considered, we found a highly significant correlation between shear wave speed and both the ultimate stress and elasticity of tendons, supporting the potential of SWS as a proxy measure for tendon mechanical properties.…”

“…Recent studies have shown that shear wave speeds are dependent on both fiber-direction and load, with load effects arising from the strain stiffening behavior of tendinous tissues (Aubry et al 2013; DeWall et al 2014b; Yeh et al 2014). It has been confirmed that ruptured tendons exhibit a reduction in shear wave speed (SWS) at and adjacent to the site of tissue damage (Chen et al 2013; DeWall et al 2014a). DeWall et al (2014a) also found local disruptions of shear wave speed in partially torn tendons.…”

“…It has been confirmed that ruptured tendons exhibit a reduction in shear wave speed (SWS) at and adjacent to the site of tissue damage (Chen et al 2013; DeWall et al 2014a). DeWall et al (2014a) also found local disruptions of shear wave speed in partially torn tendons. Thus, it is possible that SWS measurements may serve as a proxy for localized tissue elasticity, and indirectly for ultimate stress of a healing tendon (LaCroix et al 2013).…”